The present invention relates to a new and improved coupling assembly and more specifically to a coupling assembly which is relatively quiet in operation and which minimizes peak acceleration of components of the coupling assembly.
A coupling assembly having the construction illustrated in U.S. Pat. No. 4,807,731, issued Feb. 28, 1989 and entitled "Clutch and Brake Assembly", has been used to drive a machine at a rate of 250 cycles per minute or more. One machine which has been driven through this coupling assembly is a can-forming machine. During the forming of cans, the load transmitted from components of the machine to the coupling assembly varied in a range between at least +12,500 pound inches and at most -2,500 pound inches. The cyclically varying torque load is applied to the coupling assembly during each revolution of the coupling assembly while the coupling assembly is rotating at a speed of 645 revolutions per minute or more.
The magnitude of the range of the cyclically varying torque will depend on the construction of the can-forming machine and the speed of operation of the can-forming machine. For one specific can-forming machine operating at a speed of 325 cycles per minute or 838 revolutions per minute, the load transmitted from components of the machine to the coupling assembly varied in a range between +35,000 pound inches and -19,000 pound inches. Of course, the range of the torque load will vary as a function of the construction of the machine and the speed of operation of the machine.
This known clutch and brake or coupling assembly has been generally satisfactory in its mode of operation. However, during the transmission of torque through the coupling assembly, an annoying clacking noise is present.
Thus, while the clutch assembly is rotating at a speed of more than 645 rpms and the aforementioned cyclically varying torque load is applied to the clutch assembly during each revolution of the clutch assembly, a peak noise of 3.8 Pascals and 107 decibels was caused by metal-to-metal impact between elements of the coupling assembly. In addition, the coupling assembly transmitted substantial vibrational forces. Thus, components of the coupling assembly experienced a maximum peak tangential acceleration of approximately 48 g's, that is 48 times the acceleration of gravity.